1. Field of the Invention
The present invention relates to the field of medicine, and specifically to an apparatus for locating and viewing subcutaneous vessels.
2. Brief Description of the Related Art
In the field of medicine, it is common to administer fluids, and to take samples of human blood, by accessing the veins and arteries of patients. The withdrawal of blood with needles and the insertion of catheters are two common procedures which require percutaneous access to veins and arteries of a person. Fluids, such as, for example drugs, proteins and other nutrients are routinely delivered to patients by medical personnel. While some medications can be delivered orally, or intramuscularly, with a syringe and needle, in many cases it is necessary to deliver fluids and drugs directly, intravenously, into the blood stream. To do this, trained medical personnel are required to locate an appropriate vessel, such as a vein or artery, into which the fluids or drugs can be administered.
In addition, blood samples are usually obtained through veins. The puncture of a vein with a needle is a preferred way to obtain a patient""s blood sample. Also, catheterization of veins and arteries may take place through insertion of an apparatus into the vessel.
While locating and puncturing veins and arteries in adults is routinely done, it is often very difficult to locate veins of certain individuals, such as obese individuals, whose arteries are not as close to the skin surfaces as those of a person of normal weight. It is also difficult for medical personnel to locate and puncture veins and arteries of persons with very low blood pressure, and infants whose arteries are difficult to locate.
Human arteries and veins are approximately 2 to 8 millimeters in diameter. In infants, again the problems of locating and puncturing veins and arteries in order to carry out medical procedures can be very difficult or impossible at times. While physicians and other trained medical personnel sometimes have difficulty locating the veins and arteries of a healthy adult human, even more challenging, and sometimes impossible, to locate and puncture the veins and arteries of an infant. Infants, like adults, at times require surgery, administration of treatment, or other medical procedures which mandate the delivery of intravenous fluids into a vessel. Blood sampling also requires access to an infant""s blood vessels. Locating the vein of an infant can be crucial, especially in emergency situations, where it is important to find the veins as rapidly as possible so that any necessary procedures can be carried out. There is a great risk imposed on the infant patient when there is a delay in providing the needed intravenous fluid or drugs. Delay in these cases can be fatal. For example, an infant who is unable to receive a crucial intravenous delivery may dehydrate; or, if a sufficient blood sample cannot be obtained from the infant within the appropriate time frame, it may be impossible to provide the appropriate treatment, or know how much of a medication to administer.
In other instances, certain diseases require the intermittent administration of intravenous fluids. For example the treatments of many diseases, such as, major infections, renal disease, and cancer, may include continuous or intermittent intravenous therapy.
The most commonly used method for insertion of intravenous delivery devices, such as a catheter, is by percutaneous needle puncture, directly into a vessel. Again, finding the vein or artery is critical to a catheter set up.
Presently, knowledge of an infant""s anatomy is essential, and, moreover, is relied upon where the tiny infant veins are not visible. Although one may well know an infant""s anatomy, the location of veins in an infant, while having a generally identifiable location, can vary slightly in each infant. As a result, repeated needle sticks may take place before a successful puncture of the vessel is achieved. This can lead to infections due to the instances of the repeated needle sticks and their tendency to introduce bacteria into the individual. This can occur, even where the medical personnel uses the proper procedures. Therefore, even a commanding knowledge of infant anatomy does not ensure that one will find the infant""s vein on the first attempt, or even at all.
When the vein cannot be found, for example, when taking a blood sample, or when inserting an intravenous line, time for treatment administration can be compromised. In these situations, where live-saving treatment must be administered, or a blood sample obtained, it is sometimes necessary to insert a needle or catheter in the bone, such as the tibia. This is very painful to the patient, but, where life-saving treatment or access to the blood is necessary, the bone must be pierced.
In order to locate veins, it is a common practice to constrict veins in a desired area to more clearly delineate the veins. Apparatus such as straps and bands have been used for this purpose. U.S. Pat. No. 5,647,850 issued on Jul. 15, 1997 to William Allen discloses a xe2x80x9cMethod and Apparatus for Vein Locationxe2x80x9d which uses an inflatable bladder which is disposed about a patient""s limb to constrict the blood flow.
While problems locating veins and arteries have been recognized, there have been some known attempts to improve the ability to locate veins within the body. U.S. Pat. No. 3,745,989 issued on Jul. 17, 1973 to Sanford Pinna discloses a xe2x80x9cDevice for Locating Veins in Living Bodiesxe2x80x9d which provides a spring-tensioned sensor rod and a marking rod mounted for axial reciprocation to respond to the sensing of a vein to mark its location on the skin. Similarly, U.S. Pat. No. 3,782,365 issues on Jan. 1, 1974 to Sanford Pinna discloses a xe2x80x9cDetector for Locating Veins in Living Bodies.xe2x80x9d
U.S. Pat. No. 3,999,210 provides a xe2x80x9cMethod of Locating Veinxe2x80x9d which employs a temperature sensitive film for aiding in the locating of veins in the arm. The 210 patent utilizes a liquid crystal material which is encapsulated in a film, and is sensitive to temperature to provide color variations corresponding to the location of the veins.
Other attempts to locate veins have included ultrasonic devices, such as the xe2x80x9cDevice for Guiding a Surgical Needle into a Blood Vesselxe2x80x9d disclosed in U.S. Pat. No. 4,527,569, issued on Jul. 9, 1985 to Peter Kolb. U.S. Pat. No. 5,309,915 issued on May 10, 1994 to Charles Ember, discloses an xe2x80x9cApparatus for Locating Veins and Arteriesxe2x80x9d which utilizes ultrasonic signals to locate the vessel and produce an audible tone. A signal processing device utilizing a Doppler type of device is disclosed in U.S. Pat. No. 4,667,679 entitled xe2x80x9cApparatus and Method for Positioning and Puncturing an Artery and a Vein.xe2x80x9d The ""679 device provides an intermittent visible light or sound alert when the blood vessel is detected.
Infrared imaging has been used to obtain an image which is recorded on a video monitor. An example is U.S. Pat. No. 4,817,622 entitled xe2x80x9cInfrared Imager for Viewing Subcutaneous Location of Vascular Structures and Method of Usexe2x80x9d issued on Apr. 4, 1989 to Carl Pennypacker, et al. The ""622 device provides a television camera and monitor for viewing an appendage. Similarly, U.S. Pat. No. 5,519,208 entitled xe2x80x9cInfrared Aided Method and Apparatus for Venous Examinationxe2x80x9d issued on May 21, 1996 to Joel Esparza, et al. uses irradiation of the surface area of a patient to locate veins of the individual. U.S. Pat. No. 5,608,210 also entitled xe2x80x9cInfrared Aided Method and Apparatus for Venous Examinationxe2x80x9d issued on Mar. 4, 1997 to Joel Esparza, et al. discloses a headpiece which is worn by medical personnel when inserting a hypodermic needle into a vein. U.S. Pat. No. 5,678,555 issued on Oct. 21, 1997 to Peter O""Connell for a xe2x80x9cMethod of Locating and Marking Veinsxe2x80x9d discloses an infrared imaging camera and a remote viewing screen to locate the veins of a patient.
Other attempts to locate veins have involved invasive procedures where locating devices themselves, although provided to reduce trauma which can result from repeated or failed needle sticks, can also cause trauma. In U.S. Pat. 5,167,629 issued on Dec. 1, 1992 to Mathieu Vertenstein, et al., a xe2x80x9cVein Locatorxe2x80x9d is disclosed which is sutured to subcutaneous tissues at a fixed location relative to the vein. The ""629 device utilizes protuberances which can be felt by palpating the patient""s skin to locate the vein.
When carrying out procedures such an venapuncture, direct viewing of the vessel is preferred. In a person with readily visible veins, the medical personnel can easily locate the vein and perform the necessary puncture. It is this primary preferred method which is utilized whenever possible. A need exists for a device which will enable the method of directly locating and sighting vessels to be carried out in instances where the vessels are not readily observable, such as those of an infant.
A need exists for a better way to carry out the puncture of veins and arteries of infants. Specifically, it is desirable to avoid the consecutive needle sticks, to provide a time-saving, effective way to administer fluids and medicines through an intravenous line, as well as to draw blood for sampling, immediately as needed.
An apparatus for locating vessels of a patient in order to carry out medical procedures is provided. The vessels to be located can be veins or arteries. The present invention has particular applicability with respect to infants, whose veins are difficult to locate due to their small size and their location beneath the skin and tissue. The apparatus has a first light source which is positioned below the limb or appendage containing the vessel to be punctured. For example, the arm of an individual, such as an infant, may contain veins which can be punctured with a needle to obtain a blood sample. The first light source is preferably a cold light source which is positionable over a range of locations to maximize the visibility of vessels. Preferably, a support is provided on which the appendage or limb of the patient is positioned. The light source illuminates the limb from below. The light source is provided to have an intensity which can shine through the limb. This transillumination of the limb facilitates the exposure of the vein positions. A frame can be provided to support the limb and the light source. Preferably, an enclosure surrounds the limb area from which the blood sample is to be taken. One or more openings in the device provide access to the enclosed area such as, for example, apertures which can permit the hands of medical personnel to be inserted into the enclosed space in order to carry out the puncture of a vein or artery. Portholes can be provided, or alternately, can be fitted with sleeved gloves if a more sealingly enclosed environment is desired. A sight is provided at the top of the cover so that medical personnel can directly view the appendage. The sight can be provided as an opening, or can have one or more lenses associated therewith for enlarging, enhancing, or correcting the viewing.
An opening is provided in the side of the device through which the patient""s arm is inserted so that the desired appendage or area thereof is positioned within the device. Baffles can also surround the arm at the entrance to limit excess light spillage into the device. Furthermore, if necessary, an optional opening at the opposite end can be provided to permit an appendage to pass therethrough, if necessary. The openings can have removable covers.
A positionable, secondary light source can be provided to illuminate the surface of the appendage within the device.
It is a primary object of the present invention to provide a novel device for locating the blood vessels of a patient, and particularly those patients whose veins are difficult to find, such as an infant.
It is another object of the present invention to accomplish the above objects by transilluminating an appendage to facilitate locating a vein or artery.
It is another object of the present invention to provide an apparatus which can reduce trauma associated with needle punctures, and which can facilitate the speed with which a vessel can be located and punctured.
It is another object of the present invention to provide a portable device which can be carried in the field, and powered by an energy cell or rechargeable power supply.